Technisource, an IT services and staffing company with clients ranging from SMBs to Fortune 500 companies and government agencies, has been rolling out Windows 7 to both its external client as well as for its internal employees throughout this year.

Technisource (a Microsoft Gold Certified Partner) assists companies with planning, application testing, image development, deployment automation and physical deployments. The company has been involved in roughly 5,000 Windows 7 upgrades, with plans to ultimately upgrade 400,000 client seats. Most of these organizations are migrating from Windows XP, with a small percentage still sitting on Windows 2000, says James Wedeking, solutions director at Technisource.

Any companies running Vista are at the tail-end of a rollout, says Wedeking, and do not have the budget for another upgrade so soon.

General reaction to Windows 7 has been favorable, says Wedeking, with benefits such as improved deployment tools, driver compatibility, backward compatibility and 64-bit support.

Yet challenges persist.

"Smaller companies tend to gripe about the costs of replacing hardware, and larger companies have issues around application compatibility and user experience," Wedeking says. "IE8 application compatibility and Office 2007 and file compatibility with previous versions have been challenging."

Here are five of the biggest challenges that Technisource has grappled with when upgrading users to Windows 7.

Compatibility Issues Still Inevitable

Microsoft's efforts around Windows 7 compatibility have been "outstanding," says Wedeking, but there are still some major applications, such as Adobe CS3 and below, that have issues with Windows 7 and did not function properly in Technisource's experience. "These must be taken into account before a deployment can take place," he says.

The Trouble with Windows XP Mode

While Windows XP mode is a great concept, Wedeking warns that it really is a full Windows XP operating system running on a Virtual PC platform within Windows 7. It's a full system and functions as such. At best, XP Mode should be considered a temporary solution.

"XP Mode must be added to the domain and be included in a patch management program just as if it were a discrete Windows XP system," Wedeking says. "It should be considered a stepping stone toward something like application virtualization."

Because of this complexity, Windows XP Mode systems take the option of a large deployment off the table.

Companies may be better off solving application compatibility issues in other ways, says Wedeking, such as compatibility shims, application virtualization or just upgrading the application so it is compatible with Windows 7.

Don't Overlook Testing for Internet Explorer 8

Microsoft is practically begging users to move on from IE6, yet Technisource found that compatibility issues with IE8 continue to be a hurdle for many organizations. The problem is that the browser is often neglected when testing for compatibility.

"Make sure that you include IE8 in your compatibility testing phase," says Wedeking. "It is most important to validate that any enterprise applications that require browser access will continue to function properly."

Upgrading Different Windows Versions Can Be Tricky

The way the different versions are treated can make it difficult to navigate upgrades, says Wedeking. For example Vista Ultimate cannot be upgraded to Windows 7 Professional. It must be upgraded to Windows 7 Ultimate.

Don't Forget About License Management and Activation

The new MAK and KMS activations (the two models for activating Microsoft products) must be carefully monitored in any deployment scenario to make sure that you do not run out of licenses. While this may seem like a minor licensing issue, says Wedeking, by default Windows 7 loads with a built-in key that cannot be activated. This means that even if your license is not put into the system, it will function for a while and then potentially shutdown if the key is not updated within a certain period of time.